高能重离子碰撞中正负荷电粒子比单事例起伏研究

Study of Event-by-Event Fluctuations in the Charged Particle Ratio in High Energy Heavy-Ion Collisions

用强子和弦级联模型 ,JPCIAE及相应的MonteCarlo事例产生器 ,研究相对论性核 -核碰撞中有限快度区间内正负荷电粒子比单事例起伏与能量、中心度、共振态衰变及快度间隔的关系 .JPCIAE模型能够较好地符合CERN SPS能区Pb +Pb碰撞的实验结果 .本文还用此模型预言了RHIC能区Au +Au碰撞和ALICE能区Pb +Pb碰撞中的正负荷电粒子比单事例起伏 .可以看出碰撞能量、中心度、共振态衰变及快度间隔对正负荷电粒子比单事例起伏的影响都不大 .

Using a hadron and string cascade model,JPCIAE,and the corresponding Monte Carlo events generator,the behavior of the charged particle ratio event-by-event fluctuations in subsystem depending on energy,centrality,resonance decay and rapidity interval was investigated for Pb+Pb collisions at SPS and ALICE energies,and for Au+Au collisions at RHIC energies. The model results of charged particle ratio event-by-event fluctuations as a function of the rapidity interval in Pb+Pb collisions at SPS energies were comparable with the preliminary NA49 data. It turned out that the charged particle ratio fluctuation has no strong energy,centrality,resonance decay and rapidity interval dependences.